716 Froceeclings of the Boyal Society 
A description of the one new form may he conveniently appended 
here, along with a few notes upon one or two other species. 
AmyihiuTa hellis, Lym., var. tritonis. (Ph VII. figs. 1-3.) 
Diameter of disk, 12 mm. Arms, long and slender, 11 cm. 
Width of arm close to disk, without spines, 2 mm. Two mouth 
papillae on either side ; one large trapezoidal at the apex of the 
mouth angle, one of its sides coinciding with the corresponding 
margin of its fellow, the ten papillae almost enclosing the circle of 
the mouth ; the other mouth papilla is at the commencement of the 
oral process ; is acutely pointed and triangular, and is succeeded 
immediately by a diamond-shaped scale, which covers the opening 
of the first tentacle. A supplementary scale was noticed at one 
mouth-angle (fig. 1). 
Mouth shields heart-shaped, one subpentagonal. Side mouth 
shields appear to be triangular; they do not project inwards be- 
yond the median shields, and they meet each other in the position 
usually occupied by the first under-arm plate, which is absent. The 
other arm-plates are rectangular, vrith the inner and outer margins 
somewhat rounded ; farther out on the arms they form an angle, 
so that the plate is hexagonal ; the lateral margins straight and coin- 
cident with the attached margin of one of the tentacle scales. Side 
arm-plates slightly prominent where the spines are attached, not 
meeting in the middle line either above or below. Upper arm- 
plates transversely oval, but the proximal margin, instead of being 
evenly curved, forms an angle. 
Disk flat, thin, covered with small swollen overlapping scales, 
which are coarser and radially elongated near the radial shields. 
Eadial. shields, wedge-shaped, very long, about four times as long 
as wide, pointed at the proximal extremity, truncated distally, 
completely separated from each other, except perhaps at the ex- 
treme outer end, by a median and one or two lateral rows of 
elongated scales. Interbrachial spaces in the under surface covered 
with similar small scales.; three, or sometimes at the proximal end 
of the arm four, straight tapering bluntly-pointed arm-spines.. 
Two tentacle scales, one towards the axis of the arm, elongated, 
semi-oval ; one on the proximal margin of the aperture, shorter and 
more nearly circular. 
